🛠️ Ensure images are loaded in RGB format

[davnn]

📝 Description

Currently, loading grayscale images leads to errors in the visualization callback, because the channels are missing.
This change ensure that images are always loaded as RGB.

Additionally fixes:

• 🛠️ [Bug]: save_image fails to save images on Windows when trying to use Engine.predict() #1831

✨ Changes

Select what type of change your PR is:

• [ x ] 🐞 Bug fix (non-breaking change which fixes an issue)
• 🔨 Refactor (non-breaking change which refactors the code base)
• 🚀 New feature (non-breaking change which adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 📚 Documentation update
• 🔒 Security update

✅ Checklist

Before you submit your pull request, please make sure you have completed the following steps:

• 📋 I have summarized my changes in the CHANGELOG and followed the guidelines for my type of change (skip for minor changes, documentation updates, and test enhancements).
• 📚 I have made the necessary updates to the documentation (if applicable).
• 🧪 I have written tests that support my changes and prove that my fix is effective or my feature works (if applicable).

For more information about code review checklists, see the Code Review Checklist.

[samet-akcay]

Thanks for creating this PR and for your first contribution!

[samet-akcay]

@davnn, can you update the CHANGELOG.md file as well?

Other than that, it looks good to me, thanks!